I've been playing around with your people in Darlington Co. SC in 1880 & 1870 US censuses; I'm beginning to think there are some missing areas in the 1870 US census.
Just in case you haven't seen this link, there are some interesting Darlington Co maps & various names of townships. http://www.scottwilds.com/darlingtonaa2016_oct_012.htm
Also, on FamilySearch.org, I found a Darlington Co. SC partial list of voters about 1876. This could become useful https://www.familysearch.org/search/film/008191329?cat=56358
No exciting new info yet---but I'm looking. Thanks for the entertainment!